my strategy on hard

[Gadgeteer]

Hello.
Just have beaten hard. My strategy was to place a lot of cannons in the center, lots of pin-wheels in the twists upper-right path, and several dark monkeys in the top-left. (Placed pin-wheels and dart-ms on the last levels).
The main thing is to use a lot of road-spikes to ***** black bloons manually, the cannons will do the rest.

A HINT. Sometimes the game runs too fast to place spikes in time. The trick is to slow down your computer. Run several background time-consumers, and you will have a lot of time to decide where and when to place spikes!